Basic single-site nginx SSL reverse proxy with https upgrade

nginx.conf

events {
    multi_accept on;
    worker_connections 65535;
}

http {
    charset utf-8;
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    server_tokens off;
    log_not_found off;
    types_hash_max_size 2048;
    client_max_body_size 16M;

    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/xml application/json application/javascript application/rss+xml application/atom+xml image/svg+xml;

    server {
        listen 80 default_server;
        listen [::]:80 default_server;
        server_name _;
        return 301 https://$host$request_uri;
    }

    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name LISTEN.ADDRESS.TLD;

        add_header X-Frame-Options "SAMEORIGIN" always;
        add_header X-XSS-Protection "1; mode=block" always;
        add_header X-Content-Type-Options "nosniff" always;
        add_header Referrer-Policy "no-referrer-when-downgrade" always;
        add_header Content-Security-Policy "default-src 'self' http: https: data: blob: 'unsafe-inline'" always;
        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;

        ssl_certificate        /path/to/ssl.crt;
        ssl_certificate_key    /path/to/ssl.key;

        ssl_session_timeout 1d;
        ssl_session_cache shared:MozSSL:10m;
        ssl_session_tickets off;

        # For modern configurations
        #ssl_protocols TLSv1.2 TLSv1.3;
        ssl_protocols TLSv1.2 TLSv1.3;
        ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
        ssl_prefer_server_ciphers off;

        add_header Strict-Transport-Security "max-age=63072000" always;

        ssl_stapling on;
        ssl_stapling_verify on;
        resolver 1.1.1.1 1.0.0.1 8.8.8.8 8.8.4.4 208.67.222.222 208.67.220.220 valid=60s;
        resolver_timeout 2s;

        location / {
            proxy_pass http://YOUR.UPSTREAM.TLD:PORT;

            proxy_redirect http:// https://;
            proxy_http_version                      1.1;
            proxy_cache_bypass                      $http_upgrade;

            proxy_set_header Upgrade                $http_upgrade;
            proxy_set_header Connection             "upgrade";
            proxy_set_header Host                   $host;
            proxy_set_header X-Real-IP              $remote_addr;
            proxy_set_header X-Forwarded-For        $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto      $scheme;
            proxy_set_header X-Forwarded-Host       $host;
            proxy_set_header X-Forwarded-Port       $server_port;
        }
    }
}